Agreed about the gun part... what is with all the Higu plugging?
I think they moved the scene because having people just standing/sitting talking about stuff with nothing going on is sort of visually boring? So having them on the stairs and watching people move around is more visually stimulating. It's a product of the medium - in the sound novel you don't need that kind of mindless movement because you're just staring at still images anyway
Other thoughts:
Yay for game music! I am not well versed enough in the names to know what played when, but I recognized tracks I liked! which made me happy <3
Much less ff>> feeling than the previous two episodes, but still sort of jumpy.
I loved the glass crash at Battler coming into the kitchen - very well timed!
I know Maria is supposed to be kind of creepy here, but why was she constantly in supercrazy!Maria mode the whole time? And she definitely looked kind of monkey-ish at one point.. too goofy XD
Ending the episode at finding the bodies was good, but wasn't punctuated as well as it could have been. It felt like "OMG DEAD BODIES.... isn't this creepy?... okay we're done now." I guess I felt like things lingered a little too much to let stuff soak in. Let people think about that kind of thing as the credits are rolling instead
Overall not bad though!